I guess that's my point. "Worn out" in my book is "plugged". I once stood a suspected plugged cat on end and put a garden hose to it. Not near as much water flow out the other end. There's only one way to clear that. I use a broom stick to knock it all out. They sure seem to flow better after that form of maintenance! (Sound better too)

 

Tim,

In my teens I had a couple of T/A's, gutted the cat on both of them. The '87 had 60K on it, and I could not see the flashlight through it. It was a completely different car afterwards. The '84 had 185K on it and was in pretty good shape. I assume that it was the original b/c it had about the same amount of rust/corrosion that the muffler had, and I know that the muffler was the original. I think that it just depends on driving habits and quality of the gas.

So the cat in the diesels is not the honeycomb type that is on gassers? I did not know that. How restrictive are they on the diesel?